Q. What is the first thing you should do after purchasing a smart phone?
A. You must test it for defective pixels.
'Defective Pixel Test' is a utility application that allows you to test your iPhone simply for defective pixels (dead or stuck) on RGB Background.
Touch the screen to change RGB screens and check whether any of the Color R, G, or B pixels comprising the LCD is defective.
The test will be completed after testing all of the following eight RGB screens for defective pixels.
R - Red Color
G - Green Color
B - Blue Color
RG -Yellow Color
GB - Bluish Green Color
RB - Purple Color
RGB - White Color
Reverse RGB - Black Color